Analytically determining frequency and amplitude of spontaneous alpha oscillation in Jansenʼs neural mass model using the describing function method

Xu Yao^{1, 2}, Zhang Chun-Hui¹, Niebur Ernst³, Wang Jun-Song^{1, †}

(color online) Effect of the degree of nonlinearity. We set r = 0.2, smaller than its normal value r = 0.56, representing a decreased nonlinearity of the sigmoid function. In this case, there is no intersection between the red line and the blue curve. Inset: the output of the NMM.